Transport system, associated movable container and method

ABSTRACT

A transport system, including: a sensor, a controller and a power panel. The sensor determines a zone and sends a quantity information in response to a quantity of vehicles in the zone. The controller is arranged to send an output signal in accordance with the quantity information. The power panel is arranged to output a current in accordance with the output signal for driving vehicles in the zone, wherein the current is outputted to a cable extending through the zone.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/390,450, filed on Apr. 22, 2019, which claims the benefit of U.S.Provisional Application No. 62/690,631, filed on Jun. 27, 2018, whichare incorporated by reference in their entirety.

BACKGROUND

Automated Material Handling Systems (AMHS) have been widely used insemiconductor fabrication facilities (“FABS”) to automatically handleand transport groups or lots of wafers between various processingmachines (“tools”) used in chip manufacturing. A typical FAB may includeone or more floors having a plurality of process bays includingprocessing tools and wafer staging equipment, which are interconnectedby the AMHS.

Each bay may include a wafer stocker, which includes multiple bins fortemporarily holding and staging a plurality of wafer carriers during thefabrication process. The wafer carriers may include standard mechanicalinterface (SMIF) pods which may hold a plurality of 200 mm (8 inch)wafers, or front opening unified pods (FOUPs) which may hold larger 300mm (12 inch) wafers. Stockers generally include a single mast roboticlift or crane having a weight bearing capacity sufficient for lifting,inserting, and retrieving single wafer carriers one at a time from thebins. The stocker holds multiple SMIF pods or FOUPs in preparation fortransporting a SMIF or FOUP to the loadport of a processing tool.

A semiconductor FAB may include numerous types of automated and manualvehicles for moving and transporting wafer carriers throughout the FABduring the manufacturing process. These may include, for example,automatic guided vehicles (AGVs), personal guided vehicles (PGVs), railguided vehicles (RGVs), overhead shuttles (OHSs), and overhead hoisttransports (OHTs). An OHT system automatically moves OHT “vehicles” thatcarry and transport wafer carriers, such as SMIF pods or FOUPs holdingmultiple wafers, from a processing or work tool or a stocker to theloadport of another tool or other apparatus in the FAB. The OHT systemmay be used to transport vehicles within each bay (intra-bay) or betweenbays (inter-bay). The OHT system also moves empty vehicles (i.e.,vehicles without a wafer carrier) to the tool loadport or otherapparatus for receiving and removing empty or full SMIF pods or FOUPsthat may contain wafers for further transport and/or processing in othertools.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a diagram illustrating a transport system according to anembodiment of the present disclosure.

FIG. 2A to FIG. 2B are diagrams illustrating a rail, a power panel and acable extending along the rail of a transport system according to anembodiment of the present disclosure.

FIGS. 3A to 3C are diagrams illustrating a transport system according toanother embodiment of the present disclosure.

FIG. 4 is a diagram illustrating a movable container according to anembodiment of the present disclosure.

FIGS. 5A and 5B are diagrams illustrating a pickup coil transferringmagnetic field into electrical power according to an embodiment of thepresent disclosure.

FIG. 6 is a flowchart illustrating a transport method according to anembodiment of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the disclosure.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting. For example, the formation of afirst feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the disclosure are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in therespective testing measurements. Also, as used herein, the term “about”generally means within 10%, 5%, 1%, or 0.5% of a given value or range.Alternatively, the term “about” means within an acceptable standarderror of the mean when considered by one of ordinary skill in the art.Other than in the operating/working examples, or unless otherwiseexpressly specified, all of the numerical ranges, amounts, values andpercentages such as those for quantities of materials, durations oftimes, temperatures, operating conditions, ratios of amounts, and thelikes thereof disclosed herein should be understood as modified in allinstances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the present disclosureand attached claims are approximations that can vary as desired. At thevery least, each numerical parameter should at least be construed inlight of the number of reported significant digits and by applyingordinary rounding techniques. Ranges can be expressed herein as from oneendpoint to another endpoint or between two endpoints. All rangesdisclosed herein are inclusive of the endpoints, unless specifiedotherwise.

An Automated Material Handling System (AMHS) usually includes anoverhead hoist transport (OHT) system, a stocker system and otherinvolved facilities and equipment. The OHT system includes a noncontactpower supply device including a rail, an induction cable extending alongthe rail and a power panel. The power panel converts the commercialpower supply to a higher frequency, and output electrical power to theinduction cable. The OHT system occupies about 50% of total powerconsumption of the AMHS. Even when the AMHS is idle, the OHT systemstill constantly consumes power.

FIG. 1 is a diagram illustrating a transport system 100 according to anembodiment of the present disclosure. In some embodiments, the transportsystem 100 is applied to a semiconductor fabrication facility. In thisembodiment, the transport system 100 is a system applied to an AMHS in asemiconductor fabrication facility. For example, the transport system100 can be an OHT system. It should be noted that, the transport system100 may be a part of the AMHS applied to one of many floors in asemiconductor fabrication facility. The transport system 100 includes arail 110 consisting of two sides 110_1 and 110_2, a sensor 120, acontroller 130 and a power panel 140. The rail 110 carries vehicles, andthe vehicles are for transporting products (e.g., semiconductor wafers).As mentioned above, the transport system 100 is a part of the AMHS.Therefore, the rail 110 shown in FIG. 1 can be seen as a section of therail of the AMHS. It should be noted that, in another embodiment, therail 110 is a monorail, and the type of the rail 110 should not belimited by the present disclosure.

The sensor 120 is installed on the rail 110, and the sensor 120determines a zone of the rail 110. For example, the zone is determinedby the sensing range of the sensor 120, and substantially equals to thelength of the rail 110. With such configurations, the sensor 120 may beinstalled in the middle of the rail 110 to facilitate the sensing.However, this is not a limitation of the present disclosure. Alternativedesigns will be described in the paragraphs below. The sensor 120 sensesthe quantity of vehicles in the zone, i.e., on the rail 110, and sendsthe quantity information QI to the controller 130 in response to thequantity of vehicles in the zone. In this embodiment, the sensor 120 isimplemented by an infrared sensor, a touch sensor, a light guide or acamera, etc., and the implementation of the sensor 120 should not belimited by the present disclosure.

The controller 130 receives the quantity information QI and sends anoutput signal OUT to the power panel 140 in accordance with the quantityof vehicles in the zone indicated by quantity information QI. In thisembodiment, the transmission of the quantity information QI and theoutput signal OUT is done via Wireless Fidelity (Wi-Fi). In other words,the sensor 120, the controller 130 and the power panel 140 communicatesvia Wi-Fi, however, this is not a limitation of the present disclosure.The power panel 140 adjusts an output current OC in accordance with theoutput signal OUT, and outputs the output current OC to the rail 110 viainduction cables CAB_1 and CAB_2 corresponding to two sides of the rail(i.e., 110_1 and 110_2), respectively.

In this embodiment, the controller 130 may be implemented by a computer.However, in another embodiment, the controller 130 is implemented by aserver or any electronic device with computing power. These alternativedesigns should fall within the scope of the present disclosure as longas the controller 130 can transfer the information indicating thequantity of vehicles in the zone from the sensor 120 to the power panel140.

In this embodiment, the output signal OUT may directly indicate thequantity of vehicles in the zone, and the power panel 140 transfers thequantity of vehicles in the zone into the required output current OC. Inother embodiments, the output signal OUT indicates the required currentcorresponding to the quantity of vehicles in the zone, and the powerpanel 140 outputs the output current OC in accordance with the outputsignal OUT.

The power panel 140 converts the commercial power supply to a frequencysuitable for noncontact power supply, and feeds the power (i.e., theoutput current OC) to the induction cable CAB. For example, the powerpanel 140 convers the frequency of the commercial power supply (i.e., 60Hz) to about 8660 Hz. The induction cable CAB is an electric lineinstalled along the rail 110 as shown in FIG. 1 . When the outputcurrent OC passing through the induction cable CAB, a magnetic field isgenerated around the cable to wirelessly providing electric power.

Specifically, when the output signal OUT indicates that there is novehicle in the zone, the power panel 140 stops outputting or reduces theoutput current OC to the induction cable CAB. In addition, the powerpanel 140 may stop converting the commercial power supply to a higherfrequency in order to save power. When the output signal OUT indicatesthat there is only one vehicle on the rail 110, the power panel 140outputs the output current OC whose magnitude can be represented as A tothe induction cable CAB. When the output signal OUT indicates that thereare two vehicles on the rail 110, the power panel 140 outputs the outputcurrent OC whose magnitude can be represented as 2A to the inductioncable CAB. However, the relationship of the magnitude of the outputcurrent OC and the quantity of vehicles in the zone are not limited tobe proportional. In other embodiments, the output current OC outputtedby the power panel 140 and the quantity of vehicles in the zone arepositive correlated. For example, when the output signal OUT indicatesthat there is only one vehicle on the rail 110, the power panel 140outputs the output current OC whose magnitude can be represented as A tothe induction cable CAB. When the output signal OUT indicates that thereare two vehicles on the rail 110, the power panel 140 outputs the outputcurrent OC whose magnitude may be 1.5 A to the induction cable CAB. Themagnitude of the output current OC being adjusted in accordance with thequantity of vehicles in the zone is only for illustrative purpose, andit should not be limited by the present disclosure. In addition, theadjustment of the output current OC may be implemented by a currentregulator in the power panel 140.

It should be noted that, in FIG. 1 , only one cable (i.e., CAB_1 orCAB_2) is depicted along one side (i.e., 110_1 or 110_2) of the rail110. However, in other embodiments, there are more than one cable goalong one side of rail 110. FIG. 2A to FIG. 2B are diagrams illustratingthe rail 110, the power panel 140 and the induction cable CAB_1extending along one side of the rail 110 according to an embodiment ofthe present disclosure. As shown in FIG. 2A, the induction cable CAB_1consists of two lines 211 and 212, and each line carries the outputcurrent OC from the power panel 140. The line 211 extends along one side110_1 of the rail 100 on the top, while the line 212 extends along oneside 110_1 of rail 110 at the bottom. It should be noted that, theoutput current OC on the lines 211 and 212 may flow in differentdirections to generate a stronger magnetic field according to Ampere'slaw for the equipment disposed between the lines 211 and 212.

In order to maintain the function of the transport system 100 and alsoreduce the power consumption as much as possible, in one embodiment, theunit resistance of lines 211 and 222 is about 5-6 ohm/meter, and theoutput current OC is about 63-65 ampere.

As shown in FIG. 2B, the induction cable CAB_1 consists of four lines221, 222, 223 and 224, and each line carries the output current OC fromthe power panel 140. The lines 221 and 222 form a pair extending alongone side 110_1 of the rail 110 on the top, while the lines 223 and 224form a pair extending along one side 110_1 of the rail 110 at thebottom. It should be noted that, the output current OC on the pairconsisting of lines 221 and 222 and the pair consisting of lines 223 and224 may flow in different directions to generate a stronger magneticfield according to Ampere's law for the equipment disposed between thelines 221 to 224.

In order to maintain the function of the transport system 100 and alsoreduce the power consumption as much as possible, in one embodiment, theunit resistance of lines 221 to 224 is about 3.5-4 ohm/meter, and theoutput current OC is less than 63 ampere. Comparing to the embodiment ofFIG. 2A, the embodiment of FIG. 2B can reduce about 20-25% of powerconsumption under the same condition.

In the embodiment of FIG. 1 , the sensor 120 determines the zone by thesensing range thereof. With such configurations, the sensor 120 may beinstalled in the middle of the rail 110 to sense the quantity of vehiclein the zone. However, this is not a limitation of the presentdisclosure. Refer to FIG. 3A, which is a diagram illustrating atransport system 300 according to another embodiment of the presentdisclosure. The transport system 300 is similar to the transport system100 described and illustrated with reference to FIG. 1 except thesensors 321 and 322. In this embodiment, the sensors 321 and 322 areoppositely located in the middle of the rail 110 to sense the quantityof vehicles in the zone, and each sensor sends the quantity informationQI to the controller 130. With such configurations, the zone isdetermined by the sensing range of the sensors 321 and 322. However, itis only for illustrative purpose, the locations of the sensors shouldnot be limited by the embodiments of FIG. 1 and FIG. 3A.

Refer to FIG. 3B, which is a diagram illustrating a transport system300′ according to another embodiment of the present disclosure. Thetransport system 300′ is similar to the transport system 100 describedand illustrated with reference to FIG. 3A except the sensors 321′ and322′. In this embodiment, the sensors 321′ and 322′ are respectivelylocated at the entrance and the exit of the rail 110 to sense thequantity of vehicles in the zone, and each sensor sends the quantityinformation QI to the controller 130. With such configurations, the zoneis determined by the distance between the sensors 321′ and 322′.However, it is only for illustrative purpose, the locations of thesensors should not be limited by the embodiments of FIG. 1 and FIGS. 3Ato 3B.

Refer to FIG. 3C, which is a diagram illustrating a transport system300′ according to yet another embodiment of the present disclosure. Thetransport system 300″ is similar to the transport system 300′ describedand illustrated with reference to FIG. 3B except the sensors 321″ and322″. In this embodiment, the sensors 321′ and 322′ are respectivelylocated at the entrance and the exit of the rail 110, but on thedifferent side of the rail 110 to sense the quantity of vehicles in thezone, and each sensor sends the quantity information QI to thecontroller 130. With such configurations, the zone is determined asmentioned in the embodiment of FIG. 3B. Those skilled in the art shouldreadily understand that the locations of the sensors should not belimited by the embodiments of FIGS. 1, and 3A-3C. In other embodiments,the zone can be easily defined by the length of the rail 110.

FIG. 4 is a diagram illustrating a movable container 400 according to anembodiment of the present disclosure. In this embodiment, the movablecontainer 400 can be adapted to a vehicle carried by the rail 110, andthe movable container 400 coordinates with the transport system 100 or300 shown above. The movable container 400 includes a power transferringmechanism 410, a driving mechanism 420 and a back-up power mechanism430. The power transferring mechanism 410 including pickup coils 411 and412, and each pickup coil transfers the magnetic field generated fromthe output current OC on the induction cable CAB into electric power. Itshould be noted that the locations of the power transferring mechanism410, the driving mechanism 420 and the back-up power mechanism 430 areonly for illustrative, and it should not be limited by the presentdisclosure. In some embodiments, the power transferring mechanism 410may be installed on the side of the movable container 400 to sense themagnetic field generated by the induction cable CAB in accordance withthe output current OC.

Refer to FIG. 5A and FIG. 5B, which are diagrams illustrating a pickupcoil transferring magnetic field generated from the output current OCaccording to an embodiment of the present disclosure. As shown in FIG.5A, the direction of the output current OC passing through the line 211is out of the paper, and the output current OC generates acounter-clockwise magnetic field according to Ampere's law. Thecounter-clockwise magnetic field passes through the pickup coil 410_1.On the other hand, the direction of the output current OC passingthrough the line 212 is toward the paper, and the output current OCgenerates a clockwise magnetic field according to Ampere's law. Theclockwise magnetic field passes through the pickup coil 4101. The pickupcoil 410_1 transfers the magnetic fields sensed thereby into electricalpower. More specifically, the magnetic fields generated by the lines 211and 212 are sensed by the pickup coil 410_1. According to Faraday's law,the magnetic fields interact with the pickup coil 4101 to produce anelectromotive force to the driving mechanism 420.

As shown in FIG. 5B, the direction of the output current OC passingthrough the lines 221 and 222 is out of the paper, and the outputcurrent OC generates counter-clockwise magnetic fields in accordancewith Ampere's law. The counter-clockwise magnetic fields pass throughthe pickup coil 410_1. On the other hand, the direction of the outputcurrent OC passing through the lines 223 and 224 is toward the paper,and the output current OC generates clockwise magnetic fields inaccordance with Ampere's law. The clockwise magnetic fields pass throughthe pickup coil 410_1. The pickup coil 410_1 transfers the magneticfields sensed thereby into electrical power. More specifically, themagnetic fields generated by the lines 221 to 224 are sensed by thepickup coil 410_1. According to Faraday's law, the magnetic fieldsinteract with the pickup coil 4101 to produce an electromotive force tothe driving mechanism 420.

Referring back to FIG. 4 , the driving mechanism 420 receives theelectrical power from the power transferring mechanism 410, and providesa momentum to the movable container 400 to generate a displacementaccording to the received electrical power. Specifically, the drivingmechanism 420 includes a power receiving device 421 and wheels W1 to W4,wherein the power receiving device 421 receives the electrical powerfrom the power transferring mechanism 410, and drives the wheels W1 toW4 with the electrical power. It should be noted that, the movablecontainer 400 is not limited to include wheels W1 to W4. In other words,the movable container 400 may be driven by different driving mechanism.For example, the movable container 400 may include a magnetic levitationmechanism or other tools to generate a displacement in the zone inaccordance with the electrical power from the power transferringmechanism 410.

The back-up power mechanism 430 is arranged to provide a back-up powerat least to the driving mechanism 420 when a back-up mode is initiated,and being charged when a charging mode is initiated. Specifically, theback-up power mechanism 430 includes an energy storing device 431arranged to execute the charging and discharging operation. In thisembodiment, the energy storing device 431 is implemented by a capacitor.

In some embodiments, the back-up power mechanism 430 provides back-uppower to facilitate operations which may not be smoothly achieved withthe output current OC only. For example, when the output signal OUTindicating the quantity of vehicles in the zone is received, the powerpanel 140 adjusts the output current OC to maintain the function of thetransport system 100 or 300. The power panel 140 provides enough outputcurrent OC to each vehicle to prevent each vehicle from slowing down anddelaying the manufacturing schedule of the semiconductor fabricationfacility. However, the transmission speed of the quantity information QIand the output signal OUT, or the processing speed of the sensor 120 andthe controller 130, may not be fast enough to catch the variation of thequantity of vehicle in the zone. For example, the output signal OUTindicates that there is only one vehicle in the zone and the outputcurrent OC is generated for that one vehicle to cruise at a requiredspeed. When another vehicle enters the same zone, ideally, the outputcurrent OC should be adjusted in order to supply two vehicles. However,there is a possibility that the power panel 140 is unable tosimultaneously readjust the output current OC in accordance with thevehicle quantity change if signal lag occurs. Therefore, the twovehicles have to share the output current OC only designated for onevehicle. Lacking adequate output current for two vehicles keeps the twovehicles from maintaining the required speed. In this way, the back-uppower mechanism 430 is kicked off to (more specifically, the energystoring device 431) provide a back-up power to the driving mechanism 420in order to maintain the required speed.

For another example, when the movable container 400 executes aloading/unloading operation, the output current OC provided by the powerpanel 140 may be lower than a desired value. The loading/unloadingoperation may fail due to insufficient output current OC hence delayingthe manufacturing schedule of the semiconductor fabrication facility.Therefore, to facilitate the loading/unloading operation, the back-uppower mechanism 430 (more specifically, the energy storing device 431)provides the back-up power to the driving mechanism 420 to make sure theloading/unloading operation can succeed.

For yet another example, when the output current OC is not enough toaccelerate the movable container 400, the back-up power mechanism 430(more specifically, the energy storing device 431) provides supplementalpower to the driving mechanism 420 to increase the momentum andaccelerate the movable container 400.

In some embodiments, the back-up power mechanism 430 (more particularly,the energy storing device 431) is chargeable. For example, when themovable container 400 stays in the idle state, the back-up powermechanism 430 (more specifically, the energy storing device 431)receives the output current OC from the induction cable CAB to chargethe energy storing device 431. For another example, when the movablecontainer 400 slows down, that is, the momentum provided by the drivingmechanism 420 gradually decreases, the back-up power mechanism 430 (morespecifically, the energy storing device 431) receives the output currentOC from the induction cable CAB to charge the energy storing device 431.For yet another example, when the power transferring mechanism 410provides a stable electrical power reaching a predetermined value to thedriving mechanism 420, and the driving mechanism 420 provides a stablemomentum to the movable container 400 to maintain a required speed, theback-up power mechanism 430 (more specifically, the energy storingdevice 431) receives the output current OC from the induction cable CABto charge the energy storing device 431.

FIG. 6 is a flowchart illustrating a transport method 600 according toan embodiment of the present disclosure. Provided that the result issubstantially the same, the steps shown in FIG. 6 are not required to beexecuted in the exact order. The transport method 600 is summarized asbelow.

In step 601, a zone is determined on a rail.

In an embodiment, the sensor 120 determines a zone in accordance withthe sensing range of the sensor 120. In another embodiment, the sensors321 and 322 determine the zone by the distance between them, wherein thesensors 321 and 322 are disposed at the entrance and the exit of therail 110, respectively. The zone may be defined by the length of therail 110.

In step 602, determine if there is a vehicle in the zone, if yes, go tostep 603; otherwise, go to step 602.

In step 603, a quantity information is sent in response to a quantity ofvehicles in the zone.

In an embodiment, the sensor 120 sends the quantity information QIindicating the quantity of vehicle in the zone to the controller 130. Toaccurately calculate the quantity of vehicles in the zone, the sensor120 may be implemented by an infrared sensor, a touch sensor, a lightguide or a camera, etc.

In step 604, an output signal is sent in accordance with the quantityinformation.

In an embodiment, the controller 130, as a communication intermediumbetween the sensor 120 and the power panel 140, receives the quantityinformation QI indicating the quantity of vehicle in the zone, and sendsthe output signal OUT in accordance with the quantity information QL Theoutput signal OUT may directly indicate the quantity of vehicles in thezone or indicate the required output current according to the quantityof vehicles in the zone. The controller 130 may be implemented by apersonal computer, a laptop, a server, or any electronic device withcomputing power.

In step 605, a current is adjusted in accordance with the output signal.

In an embodiment, the power panel 140 receives the output signal OUT,and adjusts the output current OC in accordance with the output signalOUT. The adjustment of the output current OC may be done by a currentregulator installed within the power panel 140.

In step 606, the output current is outputted to a cable along the rail.

In an embodiment, the power panel 140 outputs the output current OC tothe induction cable CAB extending along the rail 110, wherein to achievethe noncontact power supply, the power panel 140 converts the commercialpower supply into a higher frequency.

In step 607, determine if the output current is large enough for allvehicles currently in the zone to remain a required speed, executepredetermined operation or accelerate, if yes, go to step 609;otherwise, go to step 608.

When the output signal OUT indicating the quantity of vehicles in thezone is received, the power panel 140 adjusts the output current OC tomaintain the function of the transport system 100 or 300. The powerpanel 140 provides enough output current OC to each vehicle to preventeach vehicle from slowing down and delaying the manufacturing scheduleof the semiconductor fabrication facility. However, the transmissionspeed of the quantity information QI and the output signal OUT, or theprocessing speed of the sensor 120 and the controller 130, may not befast enough to catch the variation of the quantity of vehicle in thezone. For example, the output signal OUT indicates that there is onlyone vehicle in the zone and the output current OC is generated for thatone vehicle to cruise at a required speed. When another vehicle entersthe same zone, ideally, the output current OC should be adjusted inorder to supply two vehicles. However, there is a possibility that thepower panel 140 is unable to simultaneously readjust the output currentOC in accordance with the vehicle quantity change if signal lag occurs.Therefore, the two vehicles have to share the output current OC onlydesignated for one vehicle. Lacking adequate output current for twovehicles keeps the two vehicles from maintaining the required speed.

When the movable container 400 executes a loading/unloading operation,the output current OC provided by the power panel 140 may be lower thana desired value. The loading/unloading operation may fail due toinsufficient output current OC hence delaying the manufacturing scheduleof the semiconductor fabrication facility.

When the output current OC is not enough to accelerate the movablecontainer 400, the back-up power mechanism 430 (more specifically, theenergy storing device 431) provides supplemental power to the drivingmechanism 420 to increase the momentum and accelerate the movablecontainer 400.

In the light of above, to maintain the required speed, facilitate theloading/unloading operation or accelerate the movable container 400, theback-up power mechanism 430 (more specifically, the energy storingdevice 431) is required to be activated to provide the back-up power tothe driving mechanism 420.

In step 608, a back-up power mechanism is activated.

In step 609, the method is ended.

Those skilled in the art should readily understand the transport method600 after reading the embodiments described above. The detaileddescription is omitted here.

In some embodiments, a transport system is disclosed. The transportsystem includes a sensor, a controller and a power panel. The sensordetermines a zone and sends a quantity information in response to aquantity of vehicles in the zone. The controller is arranged to send anoutput signal in accordance with the quantity information. The powerpanel is arranged to output a current in accordance with the outputsignal for driving vehicles in the zone, wherein the current isoutputted to a cable extending through the zone.

In some embodiments, a movable container is disclosed. The movablecontainer includes a power transferring mechanism and a back-up powermechanism. The power transferring mechanism includes a pickup coilarranged to transfer a magnetic field generated from a current on acable extending along a rail to a driving power to drive the movablecontainer. The back-up power mechanism is arranged to provide a back-updriving power to drive the movable container when the driving power isinsufficient to support the movable container to finish operations.

In some embodiments, a transport method is disclosed, including: sendinga quantity information indicative of a quantity of vehicles in a zone;sending an output signal in accordance with the quantity information;adjusting a current in accordance with the output signal; and outputtingthe adjusted current to a cable extending through the zone.

What is claimed is:
 1. A transport system, comprising: a sensor, whereinthe sensor determines a zone, detects a quantity of vehicles in thezone, and sends a quantity information; a controller, arranged to sendan output signal in accordance with the quantity information; and apower panel, arranged to output a current in accordance with the outputsignal for driving vehicles in the zone, wherein the current isoutputted to a cable extending through the zone.
 2. The transport systemof claim 1, further comprising: a rail for carrying the vehicles,wherein the sensor is installed on the rail.
 3. The transport system ofclaim 2, wherein the power panel stops outputting or reduces the currentwhen the output signal indicates that no vehicle is on the rail.
 4. Thetransport system of claim 1, wherein the current and the quantity ofvehicles in the zone are positively correlated.
 5. The transport systemof claim 1, wherein communication between the sensor, the controller andthe power panel is performed via Wireless Fidelity (Wi-Fi).
 6. A movablecontainer of a semiconductor fabrication facility, comprising: a powertransferring mechanism, comprising a pickup coil arranged to transfer amagnetic field generated from a current on a cable extending along arail to a driving power to drive the movable container; a back-up powermechanism, arranged to provide a back-up driving power to drive themovable container when the driving power is insufficient to support themovable container to finish operations of transporting semiconductorwafer in the semiconductor fabrication facility.
 7. The movablecontainer of claim 6, further comprising: a driving mechanism, arrangedto provide a momentum to the movable container for generating adisplacement on the rail.
 8. The movable container of claim 7, whereinthe back-up power mechanism provides the back-up power when the movablecontainer executes a loading or unloading operation.
 9. The movablecontainer of claim 7, wherein the back-up power mechanism provides theback-up power when the movable container requires a momentum strongerthan that provided by the driving mechanism.
 10. The movable containerof claim 7, wherein the back-up power mechanism comprises: an energystoring device, wherein the energy storing device is charged by thecurrent when the movable container stays in an idle state.
 11. Themovable container of claim 7, wherein the back-up power mechanismcomprises: an energy storing device, wherein the energy storing deviceis charged by the current when the momentum of the movable container issmaller than a predetermined value.
 12. The movable container of claim7, wherein the momentum is provided in accordance with the drivingpower.
 13. The movable container of claim 12, wherein the back-up powermechanism provides the back-up power when the driving power is lowerthan a predetermined value.
 14. The movable container of claim 12,wherein the back-up power mechanism comprising: an energy storingdevice, wherein the energy storing device is charged by the current whenthe driving power reaches a predetermined value.
 15. A transport method,comprising: sending a quantity information indicative of a quantity ofvehicles in a zone; sending an output signal in accordance with thequantity information; adjusting a current in accordance with the outputsignal; and outputting the adjusted current to a cable extending throughthe zone.
 16. The transport method of claim 15, further comprising:stopping outputting the adjusted current when the output signalindicates that no vehicle is in the zone.
 17. The transport method ofclaim 15, wherein the current and the quantity of vehicles in the zoneare positively correlated.
 18. The transport method of claim 15, whereinthe quantity information and the output signal are sent through WirelessFidelity (Wi-Fi).
 19. The transport method of claim 15, furthercomprising: providing a momentum toward a movable container; andproviding a back-up power to the movable container when a back-upcondition is fit.
 20. The transport method of claim 15, whereinproviding the back-up power comprises: providing the back-up power whena loading or unloading operation is being executed.